Method of stabilizing biocidal compositions of haloalkynyl compounds

ABSTRACT

This invention is directed to a method for stabilizing a composition which comprises a mixture of a halopropargyl compound. The composition can be used broadly in industrial systems and more particularly with substrates such as paints, coatings, stucco, concrete, stone, cementaceous surfaces, wood, caulking, sealants, textiles, and the like.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of ApplicationSer. No. 08/479,220 filed on Jun. 7, 1995 (now abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to biocidal compositions containing ahaloalkynyl compound, and especially a halopropargyl compound. Theinvention is particularly directed to such compositions containing suchcompounds which have been stabilized to reduce the loss of biocidalactivity due to the degradation of such compounds. The invention isespecially directed to the stabilization of compositions containingiodopropargyl carbamates, such as 3-iodo-2-propargylbutyl carbamate.

2. Description of Related Art

Both exterior and interior surfaces and substrates of all types, whenexposed to common environmental conditions, e.g. moisture, are prone toattack, discoloration and various kinds of destruction by a variety ofspecies of microorganisms, including fungi, algae, bacteria andprotozoa. As a result, there is a great need and requirement for aneffective and economical means to protect for extended periods of timeboth exterior and interior surfaces and various type substrates andcommercial formulations from the deterioration and destruction caused bysuch microorganisms.

Materials which need protection with a suitable antimicrobialcomposition include stucco, concrete, stone, cementaceous surfaces,wood, caulking, sealants, leather, plastics, textiles, biodegradablecompositions including such materials as paints and other coatingformulations, surfactants, proteins, starch-based compositions, inks,emulsions and resins as well as numerous other materials and othersubstances which may be attacked by destructive microbes.

An enormously wide variety of materials have been identified which, tovarious degrees, are effective is retarding or preventing the growth of,and accompanying destruction caused by, such microbes. Such biocidalcompounds include halogenated compounds, organometallic compounds,quaternary ammonium compounds, phenolics, metallic salts, heterocyclicamines, formaldehyde donors, organo-sulfur compounds and the like.

Formulated products that are protected against microbial attack by theinclusion of such biocidal additives must retain their biocidal activityfor a prolonged time period to be most useful. Indeed, such productsoften are used to impart a biocidal activity to another product or to asubstrate, such as wood and the like, which itself requires extendedprotection against microbial attack.

One well-known class of biocides are those containing a halopropargylmoiety, and especially an iodopropargyl moiety. Such compounds arewidely disclosed in the patent literature including U.S. Pat. Nos.3,660,499; 3,923,870; 4,259,350; 4,592,773; 4,616,004 and 4,639,460 toname a few. Included within this class of compounds are thehalopropargyl carbamates which are known primarily for their fungicidalactivity. 3-iodo-2-propargyl butyl carbamate, hereinafter also referredto as IPBC, is one of the best known and probably the most widely usedof the halopropargyl carbamate fungicides. IPBC is a highly active broadspectrum fungicide. In addition to its fungicidal activity, IPBC alsohas been associated with algaecidal activity. In this regard, GreatBritain Patent 2,138,292 and U.S. Pat. Nos. 4,915,909 and 5,082,722contain such disclosures.

As noted above, the haloalkynyl compounds, including halopropargylcompounds, and especially the halopropargyl carbamates typically areformulated with a variety of other ingredients, in both aqueous andorganic solvent mixtures. For various reasons, it is desired that thesecompositions maintain their biocidal activity for prolonged periods oftime. Unfortunately, such compositions have sometimes been observed toexperience a progressive loss in such activity. Until now, the reasonfor such degradation has not been understood. Through experimentation,however, applicants have found that one prevalent cause for the loss ofbiocidal activity in such formulations is exposure of the haloalkynylcompound to high levels of alkalinity or high levels of acidity. In anaqueous environment, such conditions involve an extreme pH condition,both acidic and basic. Applicants have discovered that by formulatingthe composition so as to neutralize the acid or alkaline source in thecomposition, or by buffering the formulation, degradation of thebiocidal haloalkynyl compound, including specifically halopropargylcompounds such as IPBC, can be significantly retarded. The inventionalso helps to ameliorate other problems, such as the formation oflacrimators or corrosion of metal containers, caused by the degradationof IPBC in solvent-based alkyd paint formulations.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is based, therefore, on the surprising discoveryof a composition and method for stabilizing the biocidal activity ofcertain formulations containing a haloalkynyl compound. The invention isspecifically directed to a composition and method for stabilizing thebiocidal activity of certain formulations containing a halopropargylcompound, and particularly a halopropargyl carbamate fungicide, that dueto the present of alkaline or acidic constituents, experiences a declinein biocidal activity with time. There are several aspects of the presentinvention. In a first aspect, the invention comprises neutralizingexcess acid or base in an aqueous composition containing the haloalkynylcompound, respectively, with a base or an acid, as appropriate to adjustthe pH of the aqueous preparation of the composition to a pH in therange of 3.0 to 8.0, preferably to a range of 4.0 to 7.7, and morepreferably to a range of 5.5 to 7.7. In another aspect, an acidic orbasic compound is added to an organic solvent-containing formulationcontaining a halopropargyl compound such as IPBC, wherein theformulation respectively contains a degradation enhancing level ofalkalinity or acidity. In still another aspect, the invention employs abuffer to keep the halopropargyl-containing formulation, either aqueousor organic solvent-based, in the proper pH range, i.e., at an acceptablelevel of alkalinity or acidity.

Thus, the present invention provides a biocidal composition comprising amixture of a halopropargyl compound and a buffer, wherein the weightratio of said halopropargyl compound to said buffer is between 50:1 to1:100 and wherein said composition is useful for providing biocidalactivity to an end-use formulation and stabilizing the end-useformulation at a pH of between 3.0 and 8.0 against degradation of saidhalopropargyl compound.

The present invention also provides a method of stabilizing a biocidalformulation containing a halopropargyl compound, said formulation havingan alkalinity or an acidity sufficient to cause degradation of saidhalopropargyl compound in the absence of added acid, base or buffer,said method comprising adding a sufficient amount of an acid, a base ora buffer to said formulation to adjust the pH of said formulation towithin the range of 3.0 to 8.0.

The present invention also comprises a method of providing an end-useformulation with biocidal activity comprising adding a sufficient amountof a mixture of a halopropargyl compound and a buffer, wherein theweight ratio of said halopropargyl compound to said buffer in saidmixture is between 50:1 to 1:100, to said end-use formulation to impartbiocidal activity to said formulation and provide said formulation witha pH within the range of 3.0 to 8.0.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 through FIG. 7 graphically present the stability of theformulations of Comparative Examples 1 through 7 and Examples 1 through6.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a composition and a method forstabilizing certain formulations containing a haloalkynyl compound. Theinvention is specifically directed to a composition and a method forreducing the degradation of halopropargyl compounds, particularly ahalopropargyl carbamate such as IPBC, in aqueous- or organicsolvent-based formulations, caused by a presence of a degradationcausing amount of alkalinity or a degradation causing amount of acidity,such as a high (alkaline) or low (acidic) pH condition. The degradationof the active halopropargyl compound results in a loss of biocidalactivity. The present invention is particularly aimed at a way forprotecting biocidal halopropargyl compounds, and especiallyiodopropargyl carbamates, against degradation by acidic and basicenvironments. The invention thus provides for stabilized compositionscontaining a biocidal halopropargyl compound.

A halopropargyl compound for use in the present invention can beidentified by the following structure:

    YC≡C-CH.sub.2 X

wherein Y is a halogen, preferably iodine and X can be (1) oxygen whichis part of an organic functional group; (2) nitrogen which is part of anorganic functional group; (3) sulfur which is part of an organicfunctional group; or (4) carbon which is part of an organic functionalgroup.

The functional group of which oxygen is a part is preferably an ether,ester, or carbamate group. The functional group of which nitrogen is apart is preferably an amine, amide, urea, nitrile, or carbamate group.The functional group of which sulfur is a part is preferably a thiol,thiane, sulfone, or sulfoxide group. The organic functional group ofwhich carbon is a part is preferably an ester, carbamate or alkyl group.

Examples of compounds which may be used as the halopropargyl compound ofthis invention are especially the fungicidally active iodopropargylderivatives. In this regard, please see U.S. Pat. Nos. 3,923,870,4,259,350, 4,592,773, 4,616,004, 4,719,227, and 4,945,109, thedisclosures of which are herein incorporated by reference. Theseiodopropargyl derivatives include compounds derived from propargyl oriodopropargyl alcohols such as the esters, ethers, acetals, carbamatesand carbonates and the iodopropargyl derivatives of pyrimidines,thiazolinones, tetrazoles, triazinones, sulfamides, benzothiazoles,ammonium salts, carboxamides, hydroxamates, and ureas. Preferred amongthese compounds is the halopropargyl carbamate, 3-iodo-2-propynyl butylcarbamate (IPBC). This compound is included within the broadly usefulclass of compounds having the generic formula: ##STR1##

Wherein R is selected from the group consisting of hydrogen, substitutedand unsubstituted alkyl groups having from 1 to 20 carbon atoms,substituted and unsubstituted aryl, alkylaryl, and aralkyl groups havingfrom 6 to 20 carbon atoms and from substituted and unsubstitutedcycloalkyl and cycloalkenyl groups of 3 to 10 carbon atoms, and m and nare independently integers from 1 to 3, i.e., m and n are notnecessarily the same.

Particularly preferred are formulations of such halopropargyl carbamateswhere m is 1 and n is 1 having the following formula: ##STR2##

Suitable R substituents include alkyls such as methyl, ethyl, propyl,n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl,octadecyl, cycloalkyls such as cyclohexyl, aryls, alkaryls and aralkylssuch as phenyl, benzyl, tolyl, cumyl, halogenated alkyls and aryls, suchas chlorobutryl and chlorophenyl, and alkoxy aryls such as ethoxyphenyland the like.

Especially preferred are such iodopropargyl carbamates as3-iodo-2-propynyl propyl carbamate, 3-iodo-2-propynyl butyl carbamate,3-iodo-2-propynyl hexyl carbamate, 3-iodo-2-propynyl cyclohexylcarbamate, 3-iodo-2-propynyl phenyl carbamate, and mixtures thereof.

The amount of the halopropargyl compound in ultimate formulations whichare stabilized in accordance with the present invention can vary widelyand an optimum amount generally is affected by the intended applicationand other components of a particular formulation. In any event,generally such formulations contain anywhere from about 0.001 to about20 percent by weight of such halopropargyl compound. Usually, suchformulations contain from 0.01 to 10 percent by weight of suchcompounds. Such formulations, protected against microbial attack by theinclusion of a halopropargyl carbamate, can be prepared from highlyconcentrated compositions of the halopropargyl active ingredients, suchas by appropriate dilution. Oftentimes, the optimum useful range isabout 0.1% to 1.0% of halopropargyl carbamate in a final formulation.Upon the use of such formulations in end use systems, it is possible toprotect surfaces as well as other substrates for extended periods oftime against microbial growth, for example, from both algae and fungi.

Compositions of the present invention will generally be formulated bymixing the halopropargyl active ingredient or a concentrate of thehalopropargyl compound in a liquid vehicle for dissolving or suspendingthe active component. The vehicle also may contain a diluent, anemulsifier and a wetting-agent. Common uses of these biocidalcompositions include protection of wood, paints and other coatings,adhesives, paper, textiles, plastics, cardboard, lubricants, caulkings,and the like. An extensive list of potential industries and applicationsfor the present invention can be found in U.S. Pat. No. 5,209,930 whichis herein incorporated by reference. Compositions containing thehalopropargyl compound fungicide, particularly an iodopropargylcarbamate such as IPBC, are often formulated as liquid mixtures, but maybe provided as wettable powders, dispersions, or in any other suitableproduct type which is desirable and most useful. In this regard,formulations to be stabilized against degradation of the activehalopropargyl biocide in accordance with the present invention can beprovided as ready-for-use products in the form of aqueous or organicsolvent solutions, dispersions, oil solutions and dispersions,emulsions, aerosol preparations and the like or as a concentrate.

Useful liquid vehicles, including organic solvents, for the halopropynylcompound, particularly the preferred iodopropynyl butyl carbamate arewater, alcohols, such as methanol, butanol and octanol, glycols, severalglycol ethers like propylene glycol n-butyl ether, propylene glycoltert-butyl ether, 2-(2-methoxymethylethoxy)-tripropylene glycol methylether, propylene glycol methyl ether, dipropyleneglycol methyl ether,tripropylenelene glycol methyl ether, propylene glycol n-butyl ether andthe esters of the previously mentioned compounds. Other useful solventsare n-methyl pyrrolidone, n-pentyl propionate, 1-methoxy-2-propanol,dibasic esters of several dicarboxylic acids and mixtures thereof, suchas the dibasic isobutyl ester blend of succinic, glutaric and adipicacids, aromatic hydrocarbons, such as xylene and toluene, high aromaticpetroleum distillates, e.g., solvent naphtha, distilled tar oil, mineraloils, ketones such as acetone, and petroleum fractions such as mineralspirits and kerosene. Other suitable organic solvents are well known tothose skilled in the art.

When preparing formulations of the present invention for specificapplications, the composition also will likely be provided with otheradjuvants conventionally employed in compositions intended for suchapplications such as organic binding agents and polymers, such as alkydresins, additional fungicides, auxiliary solvents, processing additives,fixatives, driers, such as cobalt octoate and cobalt naphthenate,plasticizers, UV-stabilizers or stability enhancers, water soluble orwater insoluble dyes, color pigments, siccatives, corrosion inhibitors,antisettlement agents, anti-skinning agents and the like. Additionalfungicides used in the composition are preferably soluble in the liquidvehicle.

Stabilized compositions of the present invention may also be an aqueous,latex-based product such as acrylic, vinyl acetate acrylic, polyvinylacetate, styrene-butadiene and silicone emulsions. They may also bemicroemulsions or microemulsion concentrates.

According to the present invention, substrates are protected frominfestation, for example by fungal and algal organisms, simply bytreating said substrate with a formulation containing a halopropargylcompound and stabilized in accordance with the present invention. Suchtreating may involve mixing the composition with the substrate, coatingor otherwise contacting the substrate with the composition and the like.As noted above, representative applications include paints, stains andother coatings, leather-treatment fluids, wood treatment compositions,metal-working fluids, water treatment, e.g., cooling water, adhesive,sealants, personal care products, paper coatings and many others.

Formulations prone to halopropargyl degradation which are stabilized inaccordance with the present invention are those compositions having anexcess of either an alkaline or an acidic component such that thecomposition has a high alkalinity or acidity, but does not necessarilyhave to be either excessively acidic or basic. For aqueous formulations,such compositions are easily identified by a simple measurement of thepH of the aqueous phase of the composition. Formulations having a pH ofabove 8.0, in more preferred practice having a pH above about 7.8, andin most preferred practice having a pH above about 7.5, to a varyingextent are prone to halopropargyl degradation. Such formulations can bestabilized by the addition of an acid or a suitable buffer.Alternatively, compositions having a pH of below 3.0, in preferredpractice compositions having a pH below about 4.0, in more preferredpractice having a pH below 5.5, and in most preferred practice having apH below about 6.5 also are prone, to a varying extent, to halopropargyldegradation. Again, such formulations can be stabilized, in this case,by the addition of a base or a suitable buffer. For organicformulations, compositions which are susceptible to halopropargyldegradation due to the presence of an excess of alkaline or acidiccomponents can be identified by treating a measured quantity of theformulation with an equal mass of water and measuring the pH of theaqueous phase. As above, formulations tested in this manner that producean aqueous phase having a pH of 8.0 and above, preferably above about7.8, and more preferably above about 7.5, or an aqueous phase having apH below 3.0, preferably below about 4.0, and more preferably below 5.4demonstrate a greater tendency to exhibit halopropargyl degradation andcan be stabilized by the addition, respectively, of an acid or a base orby the addition of a suitable buffer. Consequently, when used throughoutthe specification and claims, pH is intended to be applicable to bothaqueous-based and organic solvent-based compositions as noted above,such that the use of a pH in the specification and claims is notintended to exclude organic solvent-based formulations.

In certain alkyd-containing formulations that are used as coatings andwood preservatives, the use of drying agents (catalysts that promote oraffect the reaction of the alkyd with oxygen) may further lead to IPBCinstability. This problem is particularly encountered in formulationsemploying cobalt driers, which are generally acidic in nature. Forexample, a typical alkyd formulation might include 20-25% by weight ofan alkyd resin, 65-75% by weight of a mineral spirit solvent, 0-5% of aco-solvent such as methoxypropylacetate, 0 to 1% of an antiskinningagent such as methyl ethyl ketoxim, 0 to 1% of an antisettlementadditive such as bentonite clay, 0.1 to 1% of a drier such as cobaltoctoate, up to 4% by weight of a dye and pigment and 0.1 to 5% of IPBC.To compensate for the acidic character of the cobalt drier, as well asother driers that are commonly used with alkyds, the present inventionprovides the conjoint use of a basic co-drier (including a buffer suchas Calcium-10). In this way, the formulation is stabilized against IPBCdegradation without significantly changing the drying properties of thealkyd formulation. Whereas, calcium driers (including basic calciumdriers) have been used extensively in organic solvent-based alkydpaints, the use of these materials in a formulation also containing ahalopropargyl compound, such as IPBC, to stabilize the biocidalcomposition, has not been recognized.

According to one aspect of the method of the invention, there is addedto the halopropargyl-containing composition a sufficient amount of anacid or base, as appropriate, to adjust the pH of an aqueous mixture ofthe composition to a stabilizing pH, or there is added a sufficientamount of a suitable buffer to keep the formulation in the desired pHrange. As used in the context of the present invention, a stabilizing pHis a pH in the range of 3.0 to 8.0, preferably in the range of 4.0 to7.7, more preferably in the range of 5.5 to 7.7, and most preferably inthe range of 5.5 to 7.5. For aqueous formulations having an excess ofacidic or alkaline components, the quantity of base, acid or buffer tobe added is easily determined by routine experimentation analogous to anacid-base titration. The appropriate reagent for stabilizing theformulation, i.e., an acid, a base or a buffer, is slowly added to ameasured sample of the aqueous formulation, absent such an additive,while monitoring the pH change. Once the relative amount of reagentneeded to adjust the aqueous formulation to a pH in the range of 3.0 to8.0, preferably in the range of 4.0 to 7.7, and more preferably in therange of 5.5 to 7.7, has been determined, the same relative amount ofacid, base or buffer, as appropriate, is added to the completeformulation to stabilize it against degradation of the halopropargylcompound. For organic (non-aqueous) formulations, the same procedure canbe used except that initially an aqueous test composition must beprepared by thoroughly mixing a measured amount of the formulation withan equal mass of water. The procedure thereafter parallels the procedureoutlined above for assessing the appropriate treatment level for aqueousformulations.

The use of an appropriate buffer, added to ensure that the formulatedproduct remains in the appropriate pH range, has an advantage that anexcess of the buffering material can be used without taking theformulation into an undesirable pH range. Thus, there is no closecriticality in the total amount added, as long as at least a sufficientamount of buffer is added to prevent the degradation caused by the levelof acidity or alkalinity in the formulation. The use of a buffer has anadditional important advantage. Any strong acid or strong base thatmight be formed under the conditions of using the formulated productalso would be countered by the continuing presence of additional bufferadded into the formulated product.

Thus, a particularly important aspect of the present invention relatesto novel combinations of materials, such as solutions, dispersions,emulsions, and powders of IPBC and weakly basic materials, such asauxiliary driers (calcium, barium, etc.), salts of organic acids, etc.,or buffers that can be sold as distinct products to be used in end-useformulations and provide the pesticidal (biocidal) stability in theend-use formulation. Alternatively, the invention can be employed byadding the appropriate buffer or pH neutralizing material to the end-useformulation that contains the IPBC.

Suitable acids which can be used to adjust the pH of compositionscontaining an excess of an alkaline component include organic acids suchas formic acid, acetic acid, propionic acid, glutaric acid, 2-ethylhexanoic acid, methane sulfonic acid, lactic acid, p-toluene sulfonicacid and the like, and inorganic acids such as hydrochloric acid,sulfuric acid, phosphoric acid, boric acid and the like. Suitable basesinclude the organic bases, preferably tertiary amines, such astrimethylamine, triethylamine, triethanolamine, triisopropanolamine andthe like, and the inorganic bases such as the alkali metal hydroxides,including sodium hydroxide and ammonium hydroxide, and alkali metalcarbonates. It is preferred to use relatively weak acids and relativelyweak bases to make the above-noted pH adjustment.

As noted above, it is often preferred to use a suitable buffer, i.e., amaterial that simultaneously functions as both a weak acid and a weakbase, which is able to react with (i.e., neutralize,) both strongeracids and stronger bases. Suitable buffers include bicarbonates,carbonate esters, complex carbonate salts of organic acids, hydrogenphosphates, phosphate esters, phosphinate esters, borates, borateesters, hydrogen sulfates, sulfinates, and sulfate esters. Specificexamples of suitable buffers include potassium bicarbonate, potassiumbiphthalate, potassium bisulfate, potassium dihydrogen citrate,dipotassium hydrogen citrate, potassium dihydrogen phosphate,dipotassium hydrogen phosphate, potassium hydrogen tartrate, potassiumhydrogen oxolate, potassium hydrogen maleate, potassium hydrogensuccinate, potassium hydrogen glutarate, potassium hydrogen adipate,potassium tetraborate, potassium pentaborate, potassium octaborate andall the corresponding sodium salts, complex calcium carbonate salts oforganic acids (such as octanoic acid, iso-octanoic acid, 2-ethylhexanoic acid, hexanoic acid, and the like),2-[2-amino-2-oxoethyl)amino]ethanesulfonic acid,N-[2-acetamido]-2-aminoethanesulfonic acid,N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid,2-[bis(2-hydroxyethyl)amino]ethanesulfonic acid, and other similarmaterials known in the art.

As noted above, the acid, base or buffer is added to a formulationcontaining a halopropargyl compound which in the absence of suchadditive would exhibit a level of alkalinity or a level of aciditycomposition that would cause the premature degradation of thehalopropargyl compound,. The acid, base or buffer is added in asufficient amount to counteract such acidic or alkaline components byadjusting the pH of the formulation containing the halopropargylcompound to within the pH stable range of 3.0 to 8.0, preferably towithin the range of 4.0 to 7.7, and more preferably to a pH between 5.5and 7.7. Such pH can be measured directly in an aqueous preparation ofthe halopropargyl compound, or can be measured in a similar fashion inorganic solvent-based compositions after appropriate treatment withwater.

Generally, stabilized compositions, including both concentratedpreparations and fully formulated products are likely to contain 0.1 to50 weight percent, more usually 1 to 40 weight percent and most often 1to 25 weight percent of the active halopropargyl biocide, 0.1 to 20weight percent, more usually 1 to 15 weight percent and most often 1 to10 weight percent of the acid, base or buffer, for adjusting the pH, andthe balance of a solvent or liquid carrier; the total amount of thesethree components being equal to 100 weight percent, i.e., the sum of thehalopropargyl biocide, the acid, base or buffer for pH adjustment andthe solvent or liquid carrier constituting the total composition forpurpose of these percentages. As noted above, however, fully formulatedcomponents will also contain other ingredients, especially thosecontributing to an excess alkalinity or acidity in the composition inthe absence of the pH adjustment.

A particularly preferred aspect of the present invention relates to acomposition containing a halopropargyl compound and a buffer, asdescribed above, which can be sold as a concentrate and which is usefulas the biocidal additive for introducing the halopropargyl compound, andespecially IPBC, into both acidic and alkaline end-use formulations forproviding a stable biocidal activity. Generally, such a concentratecomprises a mixture of the halopropargyl compound and a buffer in aweight ratio of halopropargyl compound to buffer in the range of 50:1 to1:100. Such a concentrate is useful for imparting biocidal activity tothe end-use formulation while producing a formulated product having a pHbetween about 3.0 and 8.0, preferably between about 4.0 and 7.7, andmore preferably between 5.5 and 7.7. As used throughout thespecification and claims, the term "end-use formulation" is intended toembrace the wide variety of formulations which have used halopropargylcompounds for imparting biocidal activity including paints, stains andother coatings, leather-treatment fluids, wood treatment compositions,metal-working fluids, water treatment, adhesives, sealants, personalcare products, paper coatings, paper, textiles, plastics, cardboard,lubricants, caulkings, and the like. An extensive list of potentialapplications falling within the scope of the term "end-use formulation"can be found in U.S. Pat. No. 5,209,930 which is herein incorporated byreference.

The following examples are presented to illustrate and explain theinvention. Unless otherwise indicated, all references to parts andpercentages are based on weight.

EXAMPLES

The following comparative examples illustrate the degradation-producingeffect caused by excess alkaline components, i.e., excessive alkalineconditions, on compositions (samples) containing iodopropargyl butylcarbamate (IPBC). The samples were subjected to accelerated age testingby maintaining them at 45° C. while monitoring the residual amount ofIPBC every week for over a month. The test is believed to beapproximately equivalent to one year's aging at room temperatureconditions. The level of residual IPBC in the composition was monitoredby high performance liquid chromatography (HPLC). A Waters 712 WISPinstrument was used for the analysis with a Waters 486 UV detector, andan Alltech Econosphere column (25 cm by 0.46 cm) with C-18 RP packing(5μ). The mobile phase was a mixture of acetonitrile and water in avolume ratio of 6:4. The mobile phase was flowed through the column at arate of 1 ml/min and the detector wavelength was set at λ=230 nm. AllpH's were measured using a Beckman Φ34 pH meter.

Comparative Example 1

This example constituted a control for the aged alkaline samples. Asolution containing 10% IPBC was prepared by dissolving 5.0 g IPBC in amixture of 42.5 g methanol and 2.5 g of water. The solution had aninitial pH of 6.7. FIG. 1 presents the level of residual IPBC over time.

Comparative Example 2

A 10% solution of IPBC was prepared by dissolving 5.0 g IPBC in amixture of 1.0 g of the tertiary amine Barlene 12 [N-alkyl(C₁₂-C₁₆)-N,N-dimethylamine], 41.4 g methanol and 2.5 g water. Thecomposition had an initial pH of 8.8. FIGS. 1 and 2 illustrate theresidual IPBC content of this composition over time.

Comparative Example 3

A 10% solution of IPBC was prepared by dissolving 5.0 g IPBC in amixture of 1.05 g of 2-amino-2-methyl-1-propanol (AMP-95, Angus), 41.5 gmethanol and 2.45 g water. The composition had an initial pH of 9.8.FIGS. 1 and 3 illustrate the residual IPBC content of this compositionover time.

Comparative Example 4

A 10% solution of IPBC was prepared by dissolving 5.0 g IPBC, 1.0 g ofthe tertiary amine, N,N-dimethyl-ethanol amine, 41.5 g methanol and 2.5g water. The composition had an initial pH of 9.4. FIGS. 1 and 4illustrate the residual IPBC content of this composition over time.

Comparative Example 5

A 10% solution of IPBC was prepared by dissolving 5.0 g IPBC, 1.0 gammonium hydroxide, 42.2 g methanol and 1.8 g water. The composition hadan initial pH of 9.4. FIGS. 1 and 5 illustrate the residual IPBC contentof this composition over time.

Comparative Example 6

A 10% solution of IPBC was prepared by dissolving 5.0 g IPBC, 0.5 gsodium hydroxide, 42.0 g methanol and 2.5 g water. The composition hadan initial pH of 10.8. FIGS. 1 and 6 illustrate the residual IPBCcontent of this composition over time.

Example 1

A 10% solution of IPBC was prepared by codissolving 5.0 g IPBC, 1.0 g ofBarlene 12, 41.1 g methanol 0.4 g acetic acid and 2.5 g water. Theresulting composition had a pH of 6.9. FIG. 2 contrasts the stability(residual IPBC content) over time of this composition relative to thecomposition of Comparative Example 2.

Example 2

A 10% solution of IPBC was prepared by codissolving 5.0 g IPBC, 1.05 gof AMP-95, 40.7 g methanol 0.8 g acetic acid and 2.45 g water. Theresulting composition had a pH of 7.1. FIG. 3 contrasts the stability(residual IPBC content) over time of this composition relative to thecomposition of Comparative Example 3.

Example 3

A 10% solution of IPBC was prepared by codissolving 5.0 g IPBC, 1.0 gN,N-dimethyl-ethanol amine, 40.7 g methanol 0.8 g acetic acid and 2.5 gwater. The resulting composition had a pH of 7.4. FIG. 4 contrasts thestability (residual IPBC content) over time of this composition relativeto the composition of Comparative Example 4.

Example 4

A 10% solution of IPBC was prepared by codissolving 5.0 g IPBC, 1.0 gammonium hydroxide, 41.08 g methanol 1.12 g acetic acid and 1.8 g water.The resulting composition had a pH of 7.5. FIG. 5 contrasts thestability (residual IPBC content) over time of this composition relativeto the composition of Comparative Example 5.

Example 5

A 10% solution of IPBC was prepared by codissolving 5.0 g IPBC, 0.5 gsodium hydroxide, 40.67 g methanol 0.83 g acetic acid and 2.5 g water.The resulting composition had a pH of 7.7. FIG. 6 contrasts thestability (residual IPBC content) over time of this composition relativeto the composition of Comparative Example 6.

Comparative Example 7

A widely used composition for treating wood was prepared as follows. Amixture of 81.0 g of Bardac 2280 (a quaternary ammonium compound sold byLonza, Inc.) and 19.0 g of Troysan Polyphase AF-1® brand IPBC (a productcommercially available from Troy Chemical Corporation containing 40% byweight IPBC) was stirred until a homogeneous solution was obtained. Theresulting composition had a pH of 8.7. FIG. 7 presents the residual IPBCcontent of this composition over time.

Example 6

For comparison with the composition of Comparative Example 7, a mixtureof 80.0 g Bardac 2280, 19 g of Troysan Polyphase AF-1® brand IPBC and1.0 g acetic acid was prepared by mixing these ingredients until ahomogeneous solution was obtained. FIG. 7 contrasts the stability(residual IPBC content) over time of this composition relative to thecomposition of Comparative Example 7.

In both Comparative Example 7 and Example 6, the products were heat agedat 45° C. for over a one month period and the residual IPBC content ofthe composition was analyzed weekly by HPLC as above.

The data presented in FIGS. 1-7 demonstrate the degradation caused byalkaline pH conditions in aqueous compositions containing IPBC and thedegradation-retarding results obtained by acid neutralization.

Examples 7a-p

A series of tests (factorial experimental design) were conducted toevaluate the effects of several compositional variables on the stabilityof IPBC in solvent-based alkyd paints. The base formulation contained20% of the alkyd resin, 76.5% mineral spirits, 3% POLYPHASE® P-20T;0.06% of the acidic cobalt drier (when used- cobalt octoate) or 0.06% ofthe basic cobalt drier (Cobalt 21) or 0.1 % of Permadry® (Cobalt/Calcium(Co/Ca)) drier available from Troy Chemical Corporation, or 0.18%Troymax® CZ69 (Cobalt/Zirconium (Co/Zr)) drier available from TroyChemical Corporation and 0.2% methyl ethyl ketoxim (MEKO) (an antiskinagent) when used. Five formulation variables were explored: type ofalkyd resin (one with an acid value of 5.6 (low acid) and one with anacid value of 8.0 (high acid)); level of zirconium drier used (0.06% and0.23%); the type of cobalt drier used (acidic vs. basic vs. Co/Ca vs.Co/Zr); order of addition of the drier components (i.e., which drier isadded first); and the optional addition of MEKO. The variouscompositions were heat aged at 40° C. for 30 days, and the resultinglevels of active IPBC (on a residual percentage basis) in the heat-agedformulations are reported below in Tables 1 and 2. These results showthat the presence of acidic components had an adverse effect on IPBCstability and that the presence of alkaline materials improved the IPBCstability in these acidic formulations.

Example 8

In this experiment the conditions of Example 7a were repeated with theexception that a buffer having a suitable solubility in the organicsolvent was added to the formulation. In particular, a calcium carbonateester available from Troy Chemical Corporation as Calcium 10 was addedin three different levels (0.06 wt. %, 0.12 wt. % and 0.18 wt. %) in theformulation, respectively constituting 10:1; 5:1 and 3.3:1 (w:w) of theIPBC to buffer in the formulation. The amount of IPBC remaining afterheat aging at 40° C. for 30 days was 78.9%, 82.3% and 83.3%respectively. When contrasted with the result observed for untreatedExample 7a (57.7%), the stabilizing effect of the buffer on theformulation, even in the presence of the acidic cobalt drier, is readilyapparent.

While certain specific embodiments of the invention have been describedwith particularity herein, it will be recognized that variousmodifications thereof will occur to those skilled in the art and it isto be understood that such modifications and variations are to beincluded within the preview of this application and the spirit and scopeof the appended claims.

                                      TABLE 1                                     __________________________________________________________________________    Alkyd           Zr Drier                                                                              Co Drier                                                                            Order Drier Addition                                                                    MEKO                                  Experiment                                                                          Low Acid                                                                           High Acid                                                                          0.06%                                                                             0.23%                                                                             Acid                                                                             Base                                                                             Zr First                                                                           Co First                                                                           No Yes                                                                              Response                        __________________________________________________________________________    7a    57.7      57.7    57.7       57.7    57.7                                                                             57.7                              7b 91.3  91.3   91.3  91.3 91.3  91.3                                         7c 62.7   62.7 62.7  62.7   62.7 62.7                                         7d 89.4   89.4  89.4 89.4  89.4  89.4                                         7e  46.1 46.1  46.1  46.1  46.1  46.1                                         7f  56.6 56.6   56.6 56.6   56.6 56.6                                         7g  53.2  53.2 53.2   53.2 53.2  53.2                                         7h  60     60    60    60    60 60                                            AVERAGE 75.3 54.0 62.9 66.3 54.9 74.3 63.7 65.6 70   59.2 64.6              EFFECT                                                                              -21.3     +3.4    +19.4 +1.9      -10.8                                 __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Alkyd           Zr Drier                                                                              Co Drier                                                                             Order Drier Addition                                                                    MEKO                                 Experiment                                                                          Low Acid                                                                           High Acid                                                                          0.06%                                                                             0.23%                                                                             Co/Zr                                                                            Co/Ca                                                                             Zr First                                                                           Co First                                                                           No Yes                                                                              Response                       __________________________________________________________________________    7j         67.1     67.1   67.1                                                                              67.1      67.1  67.1                             7j  59.1  59.1 59.1  59.1   59.1 59.1                                         7k  65.3 65.3   65.3  65.3 65.3  65.3                                         71  46.8 46.8  46.8   46.8  46.8 46.8                                         7m 87.0   87.0  87.0  87.0 87.0  87.0                                         7n 72.4   72.4 72.4   72.4  72.4 72.4                                         7o 83.3  83.3   83.3 83.3  83.3  83.3                                         7p 67.1  67.1  67.1  67.1   67.1 67.1                                         AVERAGE 77.4 59.6 65.6 71.4 61.4 75.7 69.2 67.9 75.7 61.4 61.4              EFFECT                                                                              -17.8     +5.8    +14.3  -1.3      -14.3                                __________________________________________________________________________

We claim:
 1. A biocidal composition comprising a halopropargyl compoundand a buffer, wherein the weight ratio of said halopropargyl compound tosaid buffer is between 50:1 to 1:100 and wherein said composition isuseful for providing biocidal activity to an end-use formulation andstabilizing the end-use formulation at a pH of between 3.0 and 8.0against degradation of said halopropargyl compound.
 2. The biocidalcomposition of claim 1 wherein the halopropargyl compound is aniodopropargyl derivative selected from an iodopropargyl ester, aniodopropargyl ether, an iodopropargyl acetal, an iodopropargyl carbamateand an iodopropargyl carbonate.
 3. The biocidal composition of claim 2wherein the iodopropargyl carbamate has the formula: ##STR3## where R isselected from the group consisting of hydrogen, substituted andunsubstituted alkyl groups having from 1 to 20 carbon atoms, substitutedand unsubstituted aryl, alkylaryl, and aralkyl groups having from 6 to20 carbon atoms and from substituted and unsubstituted cycloalkyl andcycloalkenyl groups of 3 to 10 carbon atoms.
 4. The composition of claim3 wherein the buffer is selected from the group consisting ofbicarbonates, carbonate esters, complex carbonate salts of organicacids, hydrogen phosphates, phosphate esters, phosphinate esters,borates, borate esters, hydrogen sulfates, sulfinates, and sulfateesters.
 5. The composition of claim 4 wherein the buffer is selectedfrom the group consisting of potassium bicarbonate, potassiumbiphthalate, potassium bisulfate, potassium dihydrogen citrate,dipotassium hydrogen citrate, potassium dihydrogen phosphate,dipotassium hydrogen phosphate, potassium hydrogen tartrate, potassiumhydrogen oxolate, potassium hydrogen maleate, potassium hydrogensuccinate, potassium hydrogen glutarate, potassium hydrogen adipate,potassium tetraborate, potassium pentaborate, potassium octaborate,sodium bicarbonate, sodium biphthalate, sodium bisulfate, sodiumdihydrogen citrate, disodium hydrogen citrate, sodium dihydrogenphosphate, disodium hydrogen phosphate, sodium hydrogen tartrate, sodiumhydrogen oxolate, sodium hydrogen maleate, sodium hydrogen succinate,sodium hydrogen glutarate, sodium hydrogen adipate, sodium tetraborate,sodium pentaborate, sodium octaborate, complex calcium carbonate salt ofoctanoic acid, complex calcium carbonate salt of iso-octanoic acid,complex calcium carbonate salt of 2-ethyl hexanoic acid, complex calciumcarbonate salt of hexanoic acid,2-[2-amino-2-oxoethyl)amino]ethanesulfonic acid,N-[2-acetamido]-2-aminoethanesulfonic acid,N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid,2-[bis(2-hydroxyethyl) amino] ethanesulfonic acid and mixtures thereof.6. The composition of claim 5 wherein the iodopropargyl carbamate isselected from the group consisting of 3-iodo-2-propynyl propylcarbamate, 3-iodo-2-propynyl butyl carbamate, 3-iodo-2-propynyl hexylcarbamate, 3-iodo-2-propynyl cyclohexyl carbamate, 3-iodo-2-propynylphenyl carbamate, and mixtures thereof.
 7. The composition of claim 6wherein the buffer is a complex calcium carbonate salt of iso-octanoicacid.
 8. A biocidal composition comprising 3-iodo-2-propynyl butylcarbamate and a buffer, wherein the weight ratio of said3-iodo-2-propynyl butyl carbamate to said buffer is between 50:1 to1:100 and wherein said composition is useful for providing biocidalactivity to an end-use formulation and stabilizing the end-useformulation at a pH of between 3.0 and 8.0 against degradation of said3-iodo-2-propynyl butyl carbamate.
 9. The biocidal composition of claim1 wherein the composition is an organic-solvent based composition. 10.The biocidal composition of claim 6 wherein the composition is anorganic-solvent based composition.
 11. The biocidal composition of claim7 wherein the composition is an organic-solvent based composition.
 12. Amethod of stabilizing a biocidal formulation containing a halopropargylcompound, said formulation having an alkalinity or an acidity sufficientto cause degradation of said halopropargyl compound in the absence ofadded acid, base or buffer, said method comprising adding a sufficientamount of an acid, a base or a buffer to said formulation to adjust thepH of said formulation to within the range of 3.0 to 8.0.
 13. The methodof claim 12 wherein said acid, base or buffer is added in a sufficientamount to adjust the pH of said formulation to a pH in the range of 5.5to 7.7.
 14. The method of claim 13 wherein the halopropargyl compound isan iodopropargyl derivative selected from an iodopropargyl ester, aniodopropargyl ether, an iodopropargyl acetal, an iodopropargyl carbamateand an iodopropargyl carbonate.
 15. The method of claim 14 wherein theiodopropargyl carbamate has the formula: ##STR4## where R is selectedfrom the group consisting of hydrogen, substituted and unsubstitutedalkyl groups having from 1 to 20 carbon atoms, substituted andunsubstituted aryl, alkylaryl, and aralkyl groups having from 6 to 20carbon atoms and from substituted and unsubstituted cycloalkyl andcycloalkenyl groups of 3 to 10 carbon atoms.
 16. The method of claim 15wherein the iodopropargyl carbamate is selected from the groupconsisting of 3-iodo-2-propynyl propyl carbamate, 3-iodo-2-propynylbutyl carbamate, 3-iodo-2-propynyl hexyl carbamate, 3-iodo-2-propynylcyclohexyl carbamate, 3-iodo-2-propynyl phenyl carbamate, and mixturesthereof.
 17. An improved method of providing an end-use formulation withbiocidal activity comprising adding a sufficient amount of thecomposition of claim 1 to said end-use formulation to impart biocidalactivity to said formulation and provide said formulation with a pHwithin the range of 3.0 to 8.0.
 18. The method of claim 12 wherein thebiocidal formulation is an organic-solvent based composition.
 19. Themethod of claim 16 wherein the biocidal formulation is anorganic-solvent based composition.
 20. The method of claim 17 whereinsaid composition of claim 1 and said end-use formulation are each anorganic-solvent based composition.
 21. The composition of claim 8wherein said biocidal composition and said end-use formulation are eachan organic-solvent based composition.